Apparatus fob the manufacture op dental crowns



I n. T. PARKINSON. APPARATUS FOR THE MANUFACTURE OF DENTAL CROWNS.

APPLICATION FILED JULY 8. 191-6 Patented May 20, 1919.

,[TUUQZTCOTZ j via J? 1 bar /w UNITED STATES PATENT OFFICE. 1

DAVID T. .PARKINSON, or 'wIcHITA, KAivsAs.

APrARATUs non THE MANUFACTURE or DENTALCROWNS.

To all whom it may concern:

Be it known that I, DAVID T. PARKINSON,

a citizen of the United States, and resident of Wichita, county of Sedgwick, and State of Kansas, have invented an Improvement in Apparatus for the Manufacture of Dental Crowns, of which the following description, in connection withthe accompanying drawings, is a specification, like letters on the drawings representing like parts.

My present invention is an improvement in the manufacture of tooth crowns from blanks, and comprises means for use in crowning teeth and the object of the invention is to improve, simplify and perfect the same.

Heretofore it hasbeen customary, in the manufacture of dental crowns from blanks, to use a die, or a series of dies for the different teeth, made according to the standard measurements scientifically established, such dies being in two parts so as to permit the die being opened after the crowned partof the blank has been swaged outwardly ;.or the dies have been oflead or similar mate rial which had to be cut open after the crown was completed. As practically all such crowns were of less diameter at the root engagin portion than at the top or crown, it was, 0 course, impossible to have a closely fittingdie without opening it to-extract the finished crown, either by cutting it open, or by having the same in two parts. Such prior systems were unsatisfactory, being slow and expensive, particularly where a special die was cast for each tooth and then cut open, as well as in using'a two-part die which was apt to mar the crown, form ridges at the seams, and the like. A further difliculty withsthe use of prior dies has been that a different die was requisit'e for tooth crowns of different neck diameters, i. 0., where the crown fitted uponlthe root, and this necessitated a very large number of separate dies, and therefore it was often preferable to melt, mold and cast a particular die of lead or other material for each tooth crown to made. *My invention obviates all these prior difliculties, cumbersome 'I'neth ods, two-part dies, or specially molded dies, and enables a permanent metal die to be used, irrespective of the diameter of the neck of the crown blank and always enables the completed crown to be readily removed from the die without injury, and yet to produce a seamless crown quickly and perfectly.

.bfular blank of. gold,

Specification of Iietters Pate nt. Patented May 20, Application filed 11115 8, 1916. Serial No. 108,230. I

It will understood that the saving in time in manufacturing metal tooth crowns is also of great importance, and by'means of my invention a: crown blank can be quickly and almost immediately swaged out of a tulike, or any suitable metal or alloy, giving the proper contour and occluding surface to the completed crown, irrespective of the diameter of theneck of the crown or tooth platinum, silver, or the root to which it is to be afiixed. In carrying out my invention, a set of single-part, solid metal dies is provided with suitable contour for each different tooth, and a set of tubular blanks, having the proper 'diameter for the neck of the crown to fit upon the circumference of. the tooth root at the gum line. Having then prepared the real root, the measurement of its diameter is taken and a blank of corresponding diameter selected. Suchblank is then applied to the die having theparticular occluding surface contour for thetooth to be crowned, and the lower portion of the blank partially. filled with shot or other suitable expansible material. A- plunger of proper diameter to fit the neck of the blank is then utilized, and

the crown portion flared outwardly and swaged to the'tooth form in the bottom of the die, vby the application of pressure,

through a hammer or press, upon the. plunger. I have discovered that this swaging method will not enlarge the original diameter of the blank at the neck portion, where a smallamolmt of shot is employed, just sufficient to sw'age out the crown of the blank, and therefore the vdie is formed with its top or mouth open, of isuitablediameter to permit the withdrawal of the completedcfiared crown' portion.- Thus a solid die qmay be formed without any undercuts or the like, and may have the sides diverging. from; the bottom upwardly toward the top or mouth, permitting the removal ofthe completed crown and also permitting the crownswaging of metal blanksof difierent diameters..

A further feature of importance is the fact that a perfectly. fitting crown'iszalways produced, the measurement of the diameter of the to be employed.

swaging press or ing a single tooth, but it will be understood that a corresponding diefor each tooth will be employed, and blanks of proper diameter provided as above explained. It being a well known fact that natural teeth are formed after certain typical contours, which forms vary but little except in size, my system and process are peculiarly adapted for the manufacture of diflerentdiametered seamless crowns in the same die.

Referring to the drawings, illustrating a preferred embodiment-of my invention,

Figure 1 is a view, in perspective, of a tubular blank; I

2 is-a view of my novel form of solid Edie Fig. .3 1s a cross-sectional view through .the die and a blank preparatory to swaging;

Fig. i is a completely sw-aged tooth;

Fig. 5 is a view of a plunger :of suitable diameter to slidingly fit the particular blank to be used therewith; and

Fig. 6 is a cross sectional view through the die and blank after the latter has been swaged to convenient contour.

For the purpose of illustration, I have shown in the drawings a: single die, blank and plunger, .to elucidate the process of making a crown for an upper first molar. As above noted, my invention contemplates the provision of an entire set of dies, and of different diametered blanks and p'lungers or swaging tools for each diameter of blank Also, these dies may be fitted'in a: table, and adapted to be brought into proper position under the hammer of a the like. In carrying out my process, a metallic die 1, having its inner or bottom surface 2 of suitable contour for the particular molar in which the crown is provided, the die opening being flared or divergent as indicated at ,3 toward the top 4: so that a: crown may be readily lifted out after it has been swaged to the diameter permitted by the contour 2. A tubular blank 5 is then selected having its diameter of proper dimensions to fit the tooth which has been measured and for which the crown is to be made. Such blank is positioned'within the die 1, and may be held by pliers, by hand, or otherwise, and a quantity of shot or the like 6 is put in the bottom. Then a plunger 7 of corresponding diameter to that of the blank 5 is selected and applications of pressure imparted thereto by ahammer or by Copies 01 thispetent may be a machine, which rapidly swages out the crown 8 of the blank as illustrated in Figs. 4 and 6. The plunger may be then removed and the completed crown lifted out of the die 1, the flaring mouth or opening 3 per-- mitting such removal. The die can be used repeatedly and irrespective of the diameter of blank 5 to be swaged therein, and therefore a large range of different-sized crowns can be formed in onedie, providing all are for the same relative .tee'th. The plunger 7 being of proper diameter to fit the blank, will not distort nor destroy the neck portion of the blank, which will therefore fit the tooth rootof' similar or appropriate measurement and the entire process of measuring the root, selecting a blank, and swaging the crown, and fitting the completed crown onto the tooth, can be quickly effected by means of my invention. N o uneven surfaces in the crown are made as in the case of two-part dies, and no specially molded and cast die need be made which afterward must be cut open and the material remelted and cast for another tooth crown. The entire crown manufacture and fitting can be accomplished during a short time, while the patient waits, if desired, instead of requiring repeated visits and days intervals. My invention is as feasible in the manufacture of the incisors as in the making of bi-cuspids and molars.

My invention is further described and defined in the form of claim as follows An apparatus for making seamless dental crowns comprising a lower die having a cavity the bottom of which has the intaglio configuration of a: crown top, said cavity having an opening at least equal to the largest cross sectional dimension of the finished crown, a plunger adapted to receive blanks for forming the crown, and yielding material arranged in the blank at the end of the plunnger, said plunger adapted to cooperate with said lower die whereby said yielding material is forced out and the blank stretched to fit the lower portion of the lower die.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses. 1

DAVID T. PARKINSON.

WVitncsses:

E. J. ZIMMERMANN, 1%. F. TURK.

Washington, I). G. 

